[Mesa-dev] [PATCH 1/2] i965: correctly program MEDIA_VFE_STATE for compute shading

[kevin.rogovin at intel.com]

From: Kevin Rogovin <kevin.rogovin at intel.com>

Signed-off-by: Kevin Rogovin <kevin.rogovin at intel.com>
---
 src/mesa/drivers/dri/i965/genX_state_upload.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/genX_state_upload.c b/src/mesa/drivers/dri/i965/genX_state_upload.c
index 04a492539a..50ac5bc59f 100644
--- a/src/mesa/drivers/dri/i965/genX_state_upload.c
+++ b/src/mesa/drivers/dri/i965/genX_state_upload.c
@@ -4183,28 +4183,35 @@ genX(upload_cs_state)(struct brw_context *brw)
 
    brw_batch_emit(brw, GENX(MEDIA_VFE_STATE), vfe) {
       if (prog_data->total_scratch) {
-         uint32_t bo_offset;
+         uint32_t per_thread_scratch_value;
 
          if (GEN_GEN >= 8) {
             /* Broadwell's Per Thread Scratch Space is in the range [0, 11]
              * where 0 = 1k, 1 = 2k, 2 = 4k, ..., 11 = 2M.
              */
-            bo_offset = ffs(stage_state->per_thread_scratch) - 11;
+            per_thread_scratch_value = ffs(stage_state->per_thread_scratch) - 11;
          } else if (GEN_IS_HASWELL) {
             /* Haswell's Per Thread Scratch Space is in the range [0, 10]
              * where 0 = 2k, 1 = 4k, 2 = 8k, ..., 10 = 2M.
              */
-            bo_offset = ffs(stage_state->per_thread_scratch) - 12;
+            per_thread_scratch_value = ffs(stage_state->per_thread_scratch) - 12;
          } else {
             /* Earlier platforms use the range [0, 11] to mean [1kB, 12kB]
              * where 0 = 1kB, 1 = 2kB, 2 = 3kB, ..., 11 = 12kB.
              */
-            bo_offset = stage_state->per_thread_scratch / 1024 - 1;
+            per_thread_scratch_value = stage_state->per_thread_scratch / 1024 - 1;
          }
-         vfe.ScratchSpaceBasePointer =
-            rw_bo(stage_state->scratch_bo, bo_offset);
+         vfe.ScratchSpaceBasePointer = rw_bo(stage_state->scratch_bo, 0);
+         vfe.PerThreadScratchSpace = per_thread_scratch_value;
       }
 
+      /* If brw->screen->subslice_total is greater than one, then
+       * devinfo->max_cs_threads stores number of threads per sub-slice;
+       * thus we need to multiply by that number by subslices to get
+       * the actual maximum number of threads; the -1 is because the HW
+       * has a bias of 1 (would not make sense to say the maximum number
+       * of threads is 0).
+       */
       const uint32_t subslices = MAX2(brw->screen->subslice_total, 1);
       vfe.MaximumNumberofThreads = devinfo->max_cs_threads * subslices - 1;
       vfe.NumberofURBEntries = GEN_GEN >= 8 ? 2 : 0;
-- 
2.15.0